Management apparatuses adopt a method of distributing a group key to a plurality of devices, to manage the devices for each group. The management apparatus encrypts the group key with device keys distributed in advance to the devices, and transmits the group key. The management apparatus shares the device keys with the devices using, for example, an authenticated key exchange protocol.
For example, when hardware of the management apparatus is changed, the management authority is required to be transferred from the original management apparatus to a new management apparatus. To transfer the management authority, management information such as the device keys and the group keys held by the original management apparatus should be moved to the new management apparatus. However, in related art, because the new management apparatus is not capable of checking whether the received management information is right information, the management authority cannot be transferred by moving the management information. Accordingly, in related art, the new management apparatus is required to share new device keys with respective devices using an authenticated key exchange protocol or the like, to transfer the management authority. This process requires an enormous processing quantity.